In spite of high unemployment and stagnant wages, sales reported byU.S. automakers have been incredibly robust, with America’s big three automakers reporting double-digit sales growth for August.

General Motors Company (NYSE: GM), the second-largest U.S. automaker, said its August sales rose 15% year-over-year, making August its strongest month since September 2008. Ford Motor Company (NYSE: F), the largest U.S. automaker, and the Chrysler Group each realized 12% increases last month. (Source: “New Vehicle Sales,” Motor Intelligence web site, September 4, 2013.)

Interestingly—or perhaps not all that surprisingly—some non-U.S. automakers and their luxury divisions reported some of the largest gains. Maserati of N.A. Inc sales were up 49% in August, Rolls Royce sales were up 121%, and Jaguar sales were up more than 67%.

For the current year-to-date, U.S. light market vehicle deliveries total 10.64 million, a 9.6% increase over the 9.71 million sold during the same period last year. If car sales keep this pace, the U.S. is on track for its best year since 16.1 million vehicles were sold in 2007.

Why are so many more Americans buying from U.S. automakers? Thanks to better trade-in values and record-low interest rates, more and more Americans are opting to lease from U.S. automakers.

Once used primarily as a tool for attracting luxury car buyers, leasing is now an attractive option for a growing segment of the population. And it shows no signs of slowing down; the number of Americans leasing from U.S. automakers has been at least 22.5% in every month this year. During the second quarter, leases accounted for more than 27% of all sales, versus 24% in the same period last year. (Source: Trop, J., “Auto Sales Are Soaring, Propelled by Leases,” The New York Times, September 4, 2013.)

Just three years ago, 17.7% of all vehicles bought with financing were leased. In 2009, U.S. automakers General Motors (GM) and Chrysler nearly stopped leasing, but they have since bounced back. After leasing just two percent of its vehicles in 2008, GM now leases 20%. (Source: LeBeau, P., “Auto leasing surges to record high,” CNBC web site, September 3, 2013.)

Though that may not necessarily be a good thing. The average amount of finances by buyers during the second quarter climbed $812.00 to $26,526. At the same time, the average monthly payment for a new vehicle lease was down marginally ($8.00) year-over-year at $408.00. This is particularly attractive to those looking to purchase from a U.S. automaker, as the average monthly payment on a lease is about $50.00 less than it is if you assume a traditional auto loan. (Source: “U.S. auto leasing rising to record levels,” InAutoNews.com, September 3, 2013.)

With high unemployment, stagnant wages, and high personal debt levels, it’s looking less and less likely that the Federal Reserve will begin tapering its quantitative easing policy anytime soon.

At the same time, it’s a virtual certainty that the Federal Reserve will begin to taper quantitative easing at some point in 2014. As a result, bond prices will fall and yield prices will rise. This will impact U.S. automakers, regardless of whether people decide to purchase or lease.

In the short term, this means U.S. automakers could continue to be an attractive option. Over the longer term, however, U.S. automakers will run into some volatile rough patches and may not be able to sustain the current sales trajectory.